In recent years, electronic devices typified by mobile phones or portable information terminal devices have become widespread, and reducing a size and a weight and increasing a lifespan have been strongly demanded. Accordingly, as a power source, a battery, and particularly, a small and lightweight secondary battery capable of obtaining a high energy density has been under development.
In recent years, applications of the secondary battery have not been limited to the electronic devices described above, but various applications typified by electric tools such as an electric drill, electric vehicles such as an electric car, and power storage systems such as a home power server have been studied. As a power source thereof, the development of a high output and high capacity secondary battery is proceeding.
In the secondary battery, in order to increase performance, particles are disposed on a surface of a separator or in electrolytes (Patent Literature 1 to Patent Literature 3).
In the secondary battery, in order to increase performance, an additive is added to an electrolyte solution (refer to Patent Literature 4).